A 1.6mW 0.5GHz open-loop VGA with fast startup and offset calibration for UWB radios

Abstract

This paper presents a low-power fast-startup wideband VGA with a 6th-order low-pass filter function for UWB radios. A DC-coupled 6-stage open-loop topology is proposed, which includes DC offset calibration and fast-startup biasing circuits. The prototype in 90nm CMOS occupies only 0.075mm2, including decoupling capacitors and digital interfacing. The circuit consumes 1.6mW from a 1V supply, achieves −1.2dB up to 37.7dB gain with a programmable bandwidth from 80MHz to 460MHz, and achieves a startup-time of 12ns.